1. Field of the Invention
This invention relates to an original document reading apparatus, and an image copying apparatus, facsimile machine, and hybrid apparatus incorporating those apparatuses using the original document reading apparatus and, more particularly; to an apparatus having a means for reading double sides of the original document.
2. Description of Related Art
As an image reading apparatus capable of reading image information on double sides of original documents, the following apparatus has been known.
First, as disclosed in Japanese Unexamined Patent Publication No. Showa 60-96,069, Japanese Unexamined Patent Publication No. Showa 60-126,964, Japanese Unexamined Patent Publication No. Showa 62-51,367, Japanese Unexamined Patent Publication No. Showa 62-258,552, Japanese Unexamined Patent Publication No. Heisei 1-180,576, Japanese Unexamined Patent Publication No. Heisei 2-121,564, Japanese Unexamined Patent Publication No. 3-240,361, Japanese Unexamined Patent Publication No. 3-256,447 (hereinafter, referred to as xe2x80x9cprior art No. 1xe2x80x9d), an image reading apparatus reads image information on double sides of original documents at the same time by passing a document sheet between two reading means placed in opposition to each other with respect to the conveyance route of the original documents.
As disclosed in Japanese Unexamined Patent Publication No. Heisei 1-194,658 (hereinafter referred to as xe2x80x9cprior art No. 2xe2x80x9d), another image reading apparatus can read image information on double sides of original documents at the same time by passing a document sheet between two reading means placed in opposition to each other with respect to the conveyance route of the original documents and can select one side as the first page.
As disclosed in Japanese Unexamined Patent Publication No. Heisei 1-126,870 (hereinafter referred to as xe2x80x9cprior art No. 3xe2x80x9d), another image reading apparatus reads image information on an original document on one side basis with two reading means placed in opposition to each other with respect to an original document contact roller by turning the original document around or making a switchback movement of the original document.
As disclosed in Japanese Unexamined Patent Publication No. Heisei 3-265,355 (hereinafter referred to as xe2x80x9cprior art No. 4xe2x80x9d), another image reading apparatus includes reading means provided on upper and lower sides of a U-turn path and can read image information on double sides of the original document separately by each reading means by looping the original document in the U-turn path.
Those conventional image reading apparatuses raise the following problems. With the prior art No. 1 and No. 2, respective (or two) image processing means are required for processing the image information read by the respective reading means to operate the two reading means at the same time, thereby increasing the costs. Where an apparatus having a single side reading function as a standard function and a double side reading function as an option is to be developed, a standard type apparatus having the single side reading function requires two image processing means in advance, so that the apparatus likely loses a merit on costs for the apparatus for reading the single side.
In the prior art No. 3, the original document returned by the switchback is read from the rear end of the original document sheet. When images are transmitted as fax images, information on the page basis is transmitted in having different vertical directions alternatively. To avoid this inconvenience, an image reversing means for reversing the up and down of the images or an original document reversing means for reversing the up and down of the original document is required, thereby rendering this apparatus complicated.
Because the original document to be turned around is held only at the rear end of the original document by sandwiching the document with rollers when the front end of the original document most goes out of the apparatus, almost all area on the original document goes out of the original document conveyance route, thereby making the original document feed obliquely and possibly causing paper jamming. To prevent such a problem, a large original document conveyance route entirely holding the turned original document is required, but such a large conveyance route makes the apparatus larger.
It is an object of the invention to provide an apparatus smaller in size, inexpensive, and simple with improved reliability (conveyance stability) and improved throughput.
To solve the above problems, the image reading apparatus has the following structure. An image reading apparatus includes: first reading means for reading image information on one side of an original document; second reading means for reading image information on the other side of the original document;image processing means for processing the image information read by the first reading means and the second reading means; switching means for switching, to either of the first reading means and the second reading means, an input source of the image information to be transmitted to the image processing means.
With this structure, image information can be transmitted to the single image processing means by switching the two reading means, so that plural image processing means will be unnecessary, so that an electric circuit board can be made smaller, and so that the production costs can be reduced.
The image reading apparatus according to the invention may have the following structure. The image reading apparatus includes: first reading means for reading image information on one side of an original document; second reading means for reading image information on the other side of the original document; image processing means for processing the image information read by the first reading means and the second reading means; switching means for switching, to either of the first reading means and the second reading means, an input source of the image information to be transmitted to the image processing means; original document conveying means having a first conveying rotary body disposed at least on a downstream side of the first reading means and a second conveying rotary body disposed at least on an upstream side of the second reading means; original document length detecting means for detecting an original document length from the second conveying rotary body to a rear end of the original document which is being conveyed; conveying drive controlling means for driving and stopping the second conveying rotary body; conveyance route opening means for opening an conveyance route by widening a space in the conveyance route located between the first conveying rotary body and the second conveying rotary body; and operation controlling means for resuming by the conveyance route opening means the space in the conveyance route located between the first conveying rotary body and the second conveying rotary body to an original state when the original document length detecting means detects that the original document length from the second conveying rotary body to the rear end of the original document which is being conveyed is shorter than a length of the original document conveyance route between the first conveying rotary body and the second conveying rotary body.
With the above structure, the front end of the original document is received by the second conveying rotary body before the image information of the original document is read by the second reading means; looseness in the original document can be permitted which occurs as a result of conveyance of the read end of the original document by opening the original document conveyance route located between the first conveying rotary body and the second conveying rotary body; and the first reading means can read the image information on the rear end side of the original document as the front end of the original document is stopped. Therefore, the distance between the first reading means and the second reading means can be made shorter, thereby reducing the apparatus to a smaller size.
After the front end of the original document was held at the second conveying rotary body, the original document conveyance route located between the first conveying rotary body and the second conveying rotary body can be opened, and the original document conveyance route can be closed right after the looseness of the original document is gone, so that conveyance stability can be improved.
The image reading apparatus according to the invention can have the following structure. The image forming apparatus includes: the first reading means, the second reading means, the image processing me, switching means, the original document conveying means having a first conveying rotary body and a second conveying rotary body, drive controlling means for driving and stopping the second conveying rotary body; an original document conveyance route for conveying the original document by turning the original document around between the first conveying rotary body and the second conveying rotary body; and conveyance route opening and closing means for opening and closing an openable cover which constitutes a portion of the original document conveyance route. The original document is delivered from or placed on the original document conveyance route which is opened by opening the cover when image information of the original document is read by the first reading means or the second reading means.
According to the above structure, when the image information of the original document is read by the first reading means or the second reading means, the original document is delivered from or placed on the original document conveyance route which is opened by opening the cover, so that the original document is conveyed in substantially a linear manner, or reading can be done upon manual feeding sheet by sheet from the opened cover. Therefore, the conveyance route of the original document can be selected according to the kind of the original documents.
Moreover, The image reading apparatus according to the invention can have the following structure. The image forming apparatus includes: the first reading means, the second reading means, the original document feeding means, the image processing means, the switching means, the feeding drive controlling means for driving and stopping the original document feeding means, the original document conveying means having a first conveying rotary body and a second conveying rotary body, the conveying drive controlling means for driving and stopping the second conveying rotary body, the conveyance route opening means, and operation controlling means. The operation controlling means switches by the switching means to the first reading means, the input source of the image information to be transmitted to the image processing means so as to start reading image information on the subsequent original document by the first reading means at substantially the same time as completion of reading the image information of the previous original document by the second reading means, and for controlling the drive of the original document feeding means by the feeding drive controlling means.
According to the above structure, since the switching means switches to the first reading means, the input source of the image information to be transmitted to the image processing means so as to start reading image information on the subsequent original document by the first reading means at substantially the same time as completion of reading the image information of the previous original document by the second reading means, and controls the drive of the original document feeding means by the feeding drive controlling means, time required for conveying the original document other than reading time would be shortened, thereby shortening the total time for reading plural sheets of the original documents successively.